To change or not to change Glowplug CU
 

Hi all,
So if I run a rheingold test on my 2009 E70 X5, with just the ignition on I get the following error codes in the DDE.
004212 DDE: Glow plug, cylinder 1, activation, with existent No
004222 DDE: Glow plug, cylinder 2, activation, with existent No
004232 DDE: Glow plug, cylinder 3, activation, with existent No
004242 DDE: Glow plug, cylinder 4, activation, with existent No
004252 DDE: Glow plug, cylinder 5, activation, with existent No
004262 DDE: Glow plug, cylinder 6, activation, with existent No

However if I start the car and clear the errors they go away, and only come back if I leave it overnight and try again in the morning.

Do I need a new Glowplug CU, and is there any way in rheingold to test the glowplug activation?

Replace it but check thermostat
 

The GP module is prone to failure. IMHO not replacing the GPU could have some negative consequences. Also, check the coolant temperature using the hidden menu or a OBD reader, anecdotal evidence suggests that a broken thermostat (running only a bit over 60 degC) can lead to GPU ( and GP) failure.

The GPU is attached to the engine block under the intake manifold. Many remove the manifold to access the GPU. I replaced mine, w/o removing the IM, in an underground parking using a long 1/4" extension and a set of magnetic sockets. There is a video on UTube showing how to do it. The module is about $120 and if you can DIY, not an expensive fix.

Replacing the thermostat is more involved but still achievable for most who have a space and a well filled tool box.

I would change the CU first as that is the more common failure. As said above, you can change it without removing the manifold.

1. Parts on cars are not self-contained digital devices that communicate their status as perfectly accurate "good" or "bad" messages


2. Parts are declared good or bad by the DDE/DME and other computers that monitor current and voltage to these modules against respected responses.


3. The GP only activates when cold


4. Hence it would not be odd to be able to clear it after start/warm up and not have the GPs activate again until they are cold. The next time the DDE could evaluate them is at cold start.


5. It would be odd to have 6 GPs all fail together and the GPCU be AOK.

Thanks all Glowplug CU change on the way